The present invention relates to the flavor and fragrance industry. It concerns more particularly the use, as a perfuming or flavoring ingredient, of a compound of formula 
wherein the double bond in position 4 has a cis or trans configuration, or of a mixture of these compounds.
The compound of formula (I) is known from the prior art. Several authors have in fact identified 2,4,7-decatrienal formed in natural compounds during the oxidative degradation of unsaturated fatty acids. For example, R. Tressl et al. in J. Agric. Food Chem., 1977, Vol. 25, p. 459, have identified 2,4,7-decatrienal among the constituents of cooked asparagus, with the compound being formed following the degradation of fatty acids. Previously, other authors had also identified this compound as a product derived from the degradation of linolenic acid, in cooked chicken (Harkes et al., J. Am. Oil Chem. Soc., 1974, Vol. 51, p. 356), as well as in mackerel oil (Ke et al., J. Am. Oil Chem. Soc., 1975, Vol. 52, p. 349) or in French fries (Buttery et Ling, J. Agric. Food Chem., 1972, Vol. 20, p. 698). Following these identifications, 2,4,7-decatrienal was synthesised. In particular, J. Am. Oil Chem. Soc., 1972, Vol. 49, p. 555 discloses the synthesis of (2E,4E,7Z)-, respectively (2E,4Z,7Z)-2,4,7-decatrienal. Moreover, the latter document describes the characteristic odor of each one of its isomers. In particular, the odors of the latter have been described as being fishy, with the authors further concluding that 2,4,7-decatrienal was responsible for the typical fishy smell associated with oxidized linolenic acid. These fishy odors characterising the aldehyde are described as off-notes, that is to say as unpleasant, undesirable or even repulsive notes.
The present invention relates to a process to confer, improve, enhance or modify the mandarin or tangerine character of a composition or product, wherein a perceptible amount of the compound of formula (I) 
wherein the double bond in position 4 has a cis or trans configuration, or of a mixture of these compounds, is added to the composition or product.
It has now unexpectedly been found that 2,4,7-decatrienal, in the form of one of its isomers of the (2E,4Z,7Z) or (2E,4E,7Z) configuration, or in the form of a mixture of these isomers, could be advantageously used in the flavoring of usually flavored compositions or consumer products. This is particularly surprising given that, as mentioned above, this compound was until now known as a degradation product of a natural product, responsible for undesirable and repulsive off-notes.
The inventors have now been able to establish that, contrary to all expectations, this compound possesses very interesting flavoring properties, and that it develops, in particular in some specific compositions, gustatory notes which are particularly useful for the reconstitution of flavors of the mandarin or tangerine type, to which it confers a very natural character.
The present invention also relates to the use as a perfuming or flavoring ingredient of a compound of formula 
wherein the double bond in position 4 has a cis or trans configuration, or of a mixture of these compounds.
The compounds of the invention develop a fishy aromatic top note, more or less fatty and oily, depending on the specific compound selected.
Among the compounds of formula (I), (2E,4Z,7Z)-2,4,7-decatrienal is particularly appreciated. In fact, this isomer possesses a very powerful flavor and develops, besides the fishy note, a linseed oil type note, which can be advantageously used in applications in compositions as shown below. Moreover, the mixtures of (2E,4Z,7Z)-2,4,7-decatrienal together with (2E,4E,7Z)-2,4,7-decatrienal, containing a preponderant amount of (2E,4Z,7Z)-2,4,7-decatrienal, are also very much appreciated according to the invention. In particular, the mixtures comprising at least 75% of (2E,4Z,7Z)-2,4,7-decatrienal, are preferred. These mixtures develop a multi-varied aromatic note, wherein the fishy and oily characters are represented, but together with green, fruity, woody, melon, linseed oil, olive oil, cucumber or kiwi notes.
Besides their very interesting flavor, the compounds of the invention also provide a fatty and round mouthfeel, which may be advantageously used for the flavoring of a large number of products.